﻿/*! JavaScript 的 MD5 实现 */

// 括号表达式, (xxxxx) 是用来将内部的语句、表达式的结果作为一个结果.
// 常见的是将json字符串用 eval 解析时,需要 eval("(" +jsonstr+ ")");
// () 内部定义了一个空间, 里面定义的变量不会污染到全局空间,很适合做lib
// (function UMD(对象/函数名name, 上下文this, 函数/对象的定义)) 返回一个匿名函数
// 因为第一个括号内 的结果是一个函数,而函数可以这样调用: (function(形参){})(实参);
// 这种匿名函数被浏览器解析后会自动执行一次.
(function UMD(name, context, definition) {
	if (typeof module !== "undefined" && module.exports) {
		// 如果 module 存在,并且module.exports存在,则将赋值结果赋给 它
		// 可以不用管
		module.exports = definition();
	} else if (typeof define === "function" && define.amd) {
		// 如果 define 这个函数存在,应该是另一个基础类库，则使用define
		// 可以不用管
		define(definition);
	} else {
		// 简单一点,可以看成: 调用传入的definition函数，将返回的对象绑定到全局空间
		// 当然,根据传入的上下文不同,也可以绑定到其他对象下面,成为一个属性方法.
		context[name] = definition(name, context);
	}
});

("md5",this, function DEF(name, context){
	"use strict";
	// 上面的 use strict 表示严格语法模式,有错误就拒绝执行.
	// 而普通的JS,是解释执行,不执行的地方,有些错误也不影响其他代码的执行
	// 作为类库,使用严格模式是很有必要的.严格模式声明必须放到一个namespace空间的最起始处.

	//
	var old_public_api = (context || {})[name];
	// 最后要返回的对象/函数.
	function md5_func(text) {
		return hex_md5(text);
	}
	
	// 下面一堆是具体的算法... 可以先不用管
	// ///////////////////////////////////////////////////

	// 计算MD5
	var hexcase = 0;
	function hex_md5(a) {
		if (a == "")
			return a;
		return rstr2hex(rstr_md5(str2rstr_utf8(a)));
	}
	
	function hex_hmac_md5(a, b) {
		return rstr2hex(rstr_hmac_md5(str2rstr_utf8(a),
				str2rstr_utf8(b)));
	}
	
	function md5_vm_test() {
		return hex_md5("abc").toLowerCase() == "900150983cd24fb0d6963f7d28e17f72";
	}
	
	function rstr_md5(a) {
		return binl2rstr(binl_md5(rstr2binl(a), a.length * 8));
	}
	
	function rstr_hmac_md5(c, f) {
		var e = rstr2binl(c);
		if (e.length > 16) {
			e = binl_md5(e, c.length * 8);
		}
		var a = Array(16), d = Array(16);
		for (var b = 0; b < 16; b++) {
			a[b] = e[b] ^ 909522486;
			d[b] = e[b] ^ 1549556828;
		}
		var g = binl_md5(a.concat(rstr2binl(f)),
				512 + f.length * 8);
		return binl2rstr(binl_md5(d.concat(g), 512 + 128));
	}
	
	function rstr2hex(c) {
		try {
			hexcase;
		} catch (g) {
			hexcase = 0;
		}
		var f = hexcase ? "0123456789ABCDEF" : "0123456789abcdef";
		var b = "";
		var a;
		for (var d = 0; d < c.length; d++) {
			a = c.charCodeAt(d);
			b += f.charAt((a >>> 4) & 15) + f.charAt(a & 15);
		}
		return b;
	}
	
	function str2rstr_utf8(c) {
		var b = "";
		var d = -1;
		var a, e;
		while (++d < c.length) {
			a = c.charCodeAt(d);
			e = d + 1 < c.length ? c.charCodeAt(d + 1) : 0;
			if (55296 <= a && a <= 56319 && 56320 <= e	&& e <= 57343) {
				a = 65536 + ((a & 1023) << 10) + (e & 1023);
				d++;
			}
			if (a <= 127) {
				b += String.fromCharCode(a);
			} else {
				if (a <= 2047) {
					b += String.fromCharCode(
							192 | ((a >>> 6) & 31),
							128 | (a & 63));
				} else {
					if (a <= 65535) {
						b += String.fromCharCode(
								224 | ((a >>> 12) & 15),
								128 | ((a >>> 6) & 63),
								128 | (a & 63));
					} else {
						if (a <= 2097151) {
							b += String.fromCharCode(
									240 | ((a >>> 18) & 7),
									128 | ((a >>> 12) & 63),
									128 | ((a >>> 6) & 63),
									128 | (a & 63));
						}
					}
				}
			}
		}
		return b;
	}
	
	function rstr2binl(b) {
		var a = Array(b.length >> 2);
		for (var c = 0; c < a.length; c++) {
			a[c] = 0;
		}
		for (var c = 0; c < b.length * 8; c += 8) {
			a[c >> 5] |= (b.charCodeAt(c / 8) & 255) << (c % 32);
		}
		return a;
	}
	
	function binl2rstr(b) {
		var a = "";
		for (var c = 0; c < b.length * 32; c += 8) {
			a += String.fromCharCode((b[c >> 5] >>> (c % 32)) & 255);
		}
		return a;
	}
	
	function binl_md5(p, k) {
		p[k >> 5] |= 128 << ((k) % 32);
		p[(((k + 64) >>> 9) << 4) + 14] = k;
		var o = 1732584193;
		var n = -271733879;
		var m = -1732584194;
		var l = 271733878;
		for (var g = 0; g < p.length; g += 16) {
			var j = o;
			var h = n;
			var f = m;
			var e = l;
			o = md5_ff(o, n, m, l, p[g + 0], 7, -680876936);
			l = md5_ff(l, o, n, m, p[g + 1], 12, -389564586);
			m = md5_ff(m, l, o, n, p[g + 2], 17, 606105819);
			n = md5_ff(n, m, l, o, p[g + 3], 22, -1044525330);
			o = md5_ff(o, n, m, l, p[g + 4], 7, -176418897);
			l = md5_ff(l, o, n, m, p[g + 5], 12, 1200080426);
			m = md5_ff(m, l, o, n, p[g + 6], 17, -1473231341);
			n = md5_ff(n, m, l, o, p[g + 7], 22, -45705983);
			o = md5_ff(o, n, m, l, p[g + 8], 7, 1770035416);
			l = md5_ff(l, o, n, m, p[g + 9], 12, -1958414417);
			m = md5_ff(m, l, o, n, p[g + 10], 17, -42063);
			n = md5_ff(n, m, l, o, p[g + 11], 22, -1990404162);
			o = md5_ff(o, n, m, l, p[g + 12], 7, 1804603682);
			l = md5_ff(l, o, n, m, p[g + 13], 12, -40341101);
			m = md5_ff(m, l, o, n, p[g + 14], 17, -1502002290);
			n = md5_ff(n, m, l, o, p[g + 15], 22, 1236535329);
			o = md5_gg(o, n, m, l, p[g + 1], 5, -165796510);
			l = md5_gg(l, o, n, m, p[g + 6], 9, -1069501632);
			m = md5_gg(m, l, o, n, p[g + 11], 14, 643717713);
			n = md5_gg(n, m, l, o, p[g + 0], 20, -373897302);
			o = md5_gg(o, n, m, l, p[g + 5], 5, -701558691);
			l = md5_gg(l, o, n, m, p[g + 10], 9, 38016083);
			m = md5_gg(m, l, o, n, p[g + 15], 14, -660478335);
			n = md5_gg(n, m, l, o, p[g + 4], 20, -405537848);
			o = md5_gg(o, n, m, l, p[g + 9], 5, 568446438);
			l = md5_gg(l, o, n, m, p[g + 14], 9, -1019803690);
			m = md5_gg(m, l, o, n, p[g + 3], 14, -187363961);
			n = md5_gg(n, m, l, o, p[g + 8], 20, 1163531501);
			o = md5_gg(o, n, m, l, p[g + 13], 5, -1444681467);
			l = md5_gg(l, o, n, m, p[g + 2], 9, -51403784);
			m = md5_gg(m, l, o, n, p[g + 7], 14, 1735328473);
			n = md5_gg(n, m, l, o, p[g + 12], 20, -1926607734);
			o = md5_hh(o, n, m, l, p[g + 5], 4, -378558);
			l = md5_hh(l, o, n, m, p[g + 8], 11, -2022574463);
			m = md5_hh(m, l, o, n, p[g + 11], 16, 1839030562);
			n = md5_hh(n, m, l, o, p[g + 14], 23, -35309556);
			o = md5_hh(o, n, m, l, p[g + 1], 4, -1530992060);
			l = md5_hh(l, o, n, m, p[g + 4], 11, 1272893353);
			m = md5_hh(m, l, o, n, p[g + 7], 16, -155497632);
			n = md5_hh(n, m, l, o, p[g + 10], 23, -1094730640);
			o = md5_hh(o, n, m, l, p[g + 13], 4, 681279174);
			l = md5_hh(l, o, n, m, p[g + 0], 11, -358537222);
			m = md5_hh(m, l, o, n, p[g + 3], 16, -722521979);
			n = md5_hh(n, m, l, o, p[g + 6], 23, 76029189);
			o = md5_hh(o, n, m, l, p[g + 9], 4, -640364487);
			l = md5_hh(l, o, n, m, p[g + 12], 11, -421815835);
			m = md5_hh(m, l, o, n, p[g + 15], 16, 530742520);
			n = md5_hh(n, m, l, o, p[g + 2], 23, -995338651);
			o = md5_ii(o, n, m, l, p[g + 0], 6, -198630844);
			l = md5_ii(l, o, n, m, p[g + 7], 10, 1126891415);
			m = md5_ii(m, l, o, n, p[g + 14], 15, -1416354905);
			n = md5_ii(n, m, l, o, p[g + 5], 21, -57434055);
			o = md5_ii(o, n, m, l, p[g + 12], 6, 1700485571);
			l = md5_ii(l, o, n, m, p[g + 3], 10, -1894986606);
			m = md5_ii(m, l, o, n, p[g + 10], 15, -1051523);
			n = md5_ii(n, m, l, o, p[g + 1], 21, -2054922799);
			o = md5_ii(o, n, m, l, p[g + 8], 6, 1873313359);
			l = md5_ii(l, o, n, m, p[g + 15], 10, -30611744);
			m = md5_ii(m, l, o, n, p[g + 6], 15, -1560198380);
			n = md5_ii(n, m, l, o, p[g + 13], 21, 1309151649);
			o = md5_ii(o, n, m, l, p[g + 4], 6, -145523070);
			l = md5_ii(l, o, n, m, p[g + 11], 10, -1120210379);
			m = md5_ii(m, l, o, n, p[g + 2], 15, 718787259);
			n = md5_ii(n, m, l, o, p[g + 9], 21, -343485551);
			o = safe_add(o, j);
			n = safe_add(n, h);
			m = safe_add(m, f);
			l = safe_add(l, e);
		}
		return Array(o, n, m, l);
	}
	
	function md5_cmn(h, e, d, c, g, f) {
		return safe_add(bit_rol(safe_add(safe_add(e, h),
				safe_add(c, f)), g), d);
	}
	
	function md5_ff(g, f, k, j, e, i, h) {
		return md5_cmn((f & k) | ((~f) & j), g, f, e, i, h);
	}
	
	function md5_gg(g, f, k, j, e, i, h) {
		return md5_cmn((f & j) | (k & (~j)), g, f, e, i, h);
	}
	
	function md5_hh(g, f, k, j, e, i, h) {
		return md5_cmn(f ^ k ^ j, g, f, e, i, h);
	}
	
	function md5_ii(g, f, k, j, e, i, h) {
		return md5_cmn(k ^ (f | (~j)), g, f, e, i, h);
	}
	
	function safe_add(a, d) {
		var c = (a & 65535) + (d & 65535);
		var b = (a >> 16) + (d >> 16) + (c >> 16);
		return (b << 16) | (c & 65535);
	}
	
	function bit_rol(a, b) {
		return (a << b) | (a >>> (32 - b));
	}
	

	// ///////////////////////////////////////////////////

	// 避免全局命名空间冲突
	md5_func.noConflict = function publicAPI$noConflict() {
		if (context) {
			// 将那个 name还原回原来的对象
			context[name] = old_public_api;
		}
		// 返回自身,由调用的代码自己持有,保存,或赋值给某个变量
		return md5_func;
	};

	// 返回的对象,会被绑定到 MD5 之类的名字上,在外部就引用了此对象,
	// 因为闭包特性,可以利用到闭包内部方法和内部对象。 lib一般都是利用这种闭包特性,维护私有的属性、对象,
	// 对外只暴露一些方法(API),也就是 function, 外面只能调用这些API,方便内部进行逻辑控制,降低依赖.
	return md5_func;
});
